An Overview of Current Dairy Welfare Concerns from the North American PerspectiveHuman-Animal Interaction / Physical Environment / Social Environment / Health Issues / Legislative Issues / References
Research Leader, United States Department of Agriculture
Agricultural Research Service, Livestock Issues Research Unit
123B Animal Science Building
Texas Tech University
Lubbock, TX 79409-2141
It is heartening to say that progress has been made in the area of dairy cattle welfare. It is also fair to say that many dairy cattle welfare issues are still present and, in North America, several new issues have surfaced since publication of the last AHousing, Husbandry, and Welfare of Dairy Cattle@ (1995) by AWIC. The intent of this introduction to the bibliography is to share my perspective on current dairy welfare issues as they affect dairy cattle raised in North America. Clearly, this perspective will be less influenced by legislation than the European perspective. This introduction represents my personal viewpoint and not that of the National Agricultural Library or Animal Welfare Information Center. My recommendation to readers is to avail themselves of the well-organized bibliography to draw their own conclusion on the status of dairy cattle welfare.
Some welfare issues persist through time in the management of dairy cattle. These include animal abuse and neglect, lack of adequate nutrition and housing, lack of treatment for disease or injury, transportation and marketing practices, slaughter and pre-slaughter handling, breeding practices and appropriate disaster management. Along with these issues are factors that have arisen more recently due to the establishment of larger dairy herds in certain parts of the country. These include provision of shade or other cooling mechanisms, the time period cows stand on concrete or other hard surfaces prior to entering the milking parlor and lameness. Emergent issues for dairy cattle in North America are the use of recombinant bovine somatotropin (BST) and the practice of tail docking.
Identifying appropriate well-being in production systems is at best a complex issue as many interrelated variables impinge on animal welfare. Certainly, welfare within a production system can vary as much as between systems. Key components can, however, be identified and those include (but are certainly not limited to) the human-animal interaction, the physical environment, and the animal=s social environment. Part of the issue in identifying welfare in relation to management systems is that it is often a subjective measure of the entire production system. Scientific studies can reveal changes in physiology or behavior with varying management practices and environmental conditions but this science is not always applicable to assessment of animal welfare in the entire production system (Fregonesi and Leaver, 2001). We can conduct science to understand the preference of animals for their environment, however this is not always clearly related to proper animal welfare as animal preferences may change with changing environmental conditions. For example, (Fregonesi, 1999) found that dairy cows preferred to lie and stand in a straw bedded environment. Depending on management of the straw, udder health and well-being could be affected by blindly imposing this type of system not to mention environmental concerns in handling the excess straw as a waste product.
Behavior is a key discipline for understanding cattle welfare. Strides have been made in studying dairy cattle behavior particularly as it relates to the human-animal bond and the animal's fear response. We now have a number of studies that illustrate that the symbiotic relationship between caretaker and cow is one of the principle factors in determining positive animal welfare. Fearfulness in cattle affects productivity and can become increasingly severe, A fearful cow tends to be more difficult to handle, resulting in an elevated negative human response which promotes additional fearfulness by the cow. The behavior section of this bibliography contains several references to the human-animal interaction and relevance to welfare (see in particular Jago et al., 1999; Morgensen et al., 1999; Munksgaard et al., 1997; Rushen et al., 1999).
Acute events and stressors that are more chronic can affect welfare. Chronic stress may ultimately lead to alterations in the animals ability to react to novel stimuli within their environment and they may become hypo or hyper reactive to such stimuli (Boissy et al., 2001). More recently we have seen the concept of positive human-animal interaction and welfare extended to fear responses, health and productivity of calves in veal units (Lensink et al., 2001). Obviously, this is a fruitful area of research and an important one for further studies.
It is estimated that about 25% of all dairy cattle in North America are housed in a free-stall environment. Here cows can enter and leave the stall at will. The stall has some form of bedding material such as sand, sawdust or possibly straw. Research has shown that a properly designed stall is necessary for proper animal welfare with key points being adequate numbers of stalls, length sufficient to prevent the udder from contacting manure in the gutters and comfort of the bedding material within the stall. The most predominant environment for dairy cattle in North America remains the tie-stall, where the cow is confined to the stall by a neck tether, which allows her to lie down, but not to turn around within the stall or leave the stall at will. A minority of dairy cows are kept on pasture throughout the year. The use of straw bedded loose housing systems (developed in Europe) are not utilized to any great extent in North America. Lying times for cows tend to be greater for cows in loose housing and freestall systems but this is dependent on management of the environment within each system. Certainly, welfare can be affected by these environmental conditions but few side-by-side comparisons of all systems exist to provide definitive information on which system is best for cow welfare.
Use of dry lot environment for dairy cows has become increasingly popular. This is due to the increase in size and number of dairies in the western and southwestern states of the US. These dry lot environments consist of large dirt paddocks with a central milking parlor. Sometimes cattle will have access to shade or other cooling device within the dry lot. Concern has recently arisen regarding the time period animals in large groups stand on hard surfaces while waiting to be milked and its association with increased lameness and culling rates for lameness in these herds. This is a particular concern for dairies with large numbers of cows and insufficient milking parlors. Cooling high-producing dairy cows has always been an issue in hot climates and may have reached its pinnacle in drylot systems as genetic selection for high productivity in more temperate climates may have negatively influenced the dairy cow's ability to adapt to heat stress (Ravagnolo et al., 2000).
Calf rearing practices where animals are individually housed and cannot turn around can be a welfare issue. These young animals are social and in some environments, they are unable to express social behavior completely. Many European systems, particularly straw-bedded group housing systems have been developed but are not used to any extent in North America. Again, it is a question of having solid research data comparing, in the same study, all systems with consideration of animal welfare, productivity, economics, and environmental impact. Until such information is available, we will continue to question which environments and production systems are best for calves.
Welfare in group housed dairy animals is strongly affected by the social environment. Animal density and mixing of cattle are disruptive to the social order and can certainly impact welfare. Cattle have elaborate social structures, being group animals and we have found that their behavior is more complex than what was thought earlier. They can show complex learning, leading us to rethink the effects of some management practices used on dairy cattle well-being. How we incorporate new heifers into an established group of cows or train heifers to the routine of milking is an area that has recently received more research attention. As we attempt to reduce stress on these animals and improve their welfare, additional questions regarding their cognitive abilities will need to be addressed by research.
Lameness certainly stands out as a consequential and complex welfare problem in dairy cattle. The complexity arises because lameness is an overt sign of many clinical, environmental and management problems. Many factors influence hoof health including genetics, conformation, diet, contagious agents, hygiene, housing system, animal behavior and management (Bergsten, 2001). A key issue in the problem of lameness has been our inability to detect it at an early stage. Recent research by Rajkondawar et al. (2001) indicates that it may be possible to use engineering tools to identify lameness in the cow in its very early stages where it is still easily treatable with a high probability of success. Continued research along these lines will assist dairy producers in their constant fight against the huge welfare problem of lameness. The associations between social rank, behavior and lameness have also recently been studied showing that lower ranking cows spend more time standing. The lower the social rank of the individual cow, the higher the probability that she will become lame (Galindo and Broom, 2000).
Recombinant bovine somatotropin or BST has been a controversial issue in both Europe and North America. Estimates suggest that over the past eight or so years since BST has been available for use in this country (FDA approval occurred on November 5, 1993), approximately 25% of US producers use BST in their herd (Fetrow, 2001). The European Union (EU) however, continues to prohibit the marketing and use of BST based on a report from their Scientific Committee on Animal Health and Animal Welfare that concluded that BST should not be used from the standpoint of its effect on cow health and welfare. Is BST a welfare issue? Clearly, it is a political "hot potato". If one considers the average time period in which cows spend in the milking herd as an indicator of welfare, then the use of BST could be a welfare issue (Kronfeld, 2000). How much is too much production? High production is correlated with both lameness and mastitis. The EU cited both of these issues as indicators to ban the use of BST in the EU.
Dehorning, or the removal of the horn buds in young calves (mainly replacement heifers) has been practiced for a number of years. Non-mechanical means of ridding cattle of horns, such as genetic selection for polled (animals without horns) dairy cattle has received little attention from the dairy industry. Since we continue the practice of dehorning, current research has focused on developing analgesic agents for dehorning calves including nonsteroidal anti-inflammatory drugs such as ketoprofen (Faulkner and Weary, 2000). As long as these standard agricultural practices are used, improving the number and availability of analgesic (particularly long lasting) agents will be a productive topic for research.
The practice of tail docking has increased in North America of late. The practice first became popular in New Zealand as a prevention against the infection of milkers with Leptospirosis. In its early history the practice of tail docking was thought to reduce mastitis as well, although no scientific evidence substantiates this claim. As a scientist, I am astonished at the behavioral and physiological response of adult cows after having a tight rubber ring placed in between the vertebrae of their tails. Cows showed no behaviors that would be suggestive of a pain or stress response (Eicher et al., 2000). On the other hand, research reports from the scientific community have suggested that docking tails may be detrimental to cows at a later time which would in fact affect their long-term welfare. Several studies in both New Zealand and North America have shown that behavior of cattle in response to flies is changed following tail docking.
Without doubt, transport of "downer cows" or nonambulatory animals is an issue, which still has not been fully addressed. Grandin (1998) reported that a large proportion of the severely lame animals arriving at slaughter are dairy and that the handling of these animals at the packing plant remains a welfare issue. Clearly, research to identify on-farm management to prevent nonambulatory cattle is needed. The legislative bent to this issue is to amend the current Code of Federal Regulations (Title 9, Section 313.2) to allow USDA inspectors to conduct ante-mortem inspection of cattle before they are removed from the transport vehicle. If this were possible, the nonambulatory animal could be euthanised before removal from the truck. The US Animal Health Association Animal Welfare Committee has also been working towards drafting language that could be used on a state-by-state basis to prohibit the transportation of nonanmbulatory animals.
Dairy cattle have received less attention from the general public and animal activist groups as having welfare problems. Society may view dairy cows as well treated, usually kept in social groups with access to a barn, pasture, food and water. This does not mean that research on dairy cattle welfare is not necessary. What should be emphasized in the future is a holistic approach to identify production systems where animal welfare is a key component along with production, food safety and environmental issues. We have made progress, as evidenced by this revised bibliography. I hope that a review of the materials presented in this bibliography will ignite the academic community and those involved in the dairy industry to continue to improve the welfare of dairy cattle under our stewardship.
(9 CFR) Code of Federal Regulations Title 9, Sec. 313.2 (d) (2) (1997). Handling of livestock. National Archives and Records Administration: Washington, D.C.
Bergsten, C. (2001). Effects of conformation and management system on hoof and leg diseases and lameness in dairy cows. Veterinary Clinics of North America: Food Animal Practice 17: 1-23.
Boissy, A., I. Veissier, and S. Roussel. (2001). Behavioural reactivity affected by chronic stress: An experimental approach in calves submitted to environmental instability. Animal Welfare 10: 175-185.
Eicher, S.D., J.L. Morrow-Tesch, J.L. Albright, J.W. Dailey, C.R. Young, and L.H. Stanker (2000). Tail-docking influences on behavioural, immunological, and endocrine responses in dairy heifers. Journal of Dairy Science 83: 1456-1462.
Faulkner, P.M., and D.M. Weary. (2000). Reducing pain after dehorning in dairy calves. Journal of Dairy Science. 83: 2037-2041.
Fetrow, J.P. (2001). Commentary: Food animal welfare and the use of bovine somatotropin. Journal of the American Veterinary Medical Association. 218: 1886-1889.
Fregonesi, J.A. (1999). Production and behaviour of dairy cattle in different housing systems. University of London, Ph.D. Thesis.
Fregonesi, J.A., and L.D. Leaver (2001). Behaviour, performance and health indicators of welfare for dairy cows housed in strawyard or cubicle systems. Livestock Production Science. 68: 205-216.
Galindo, F. and D.M. Broom. (2000). The relationships between social behaviour of dairy cows and the occurrence of lameness in three herds. Research in Veterinary Science 69: 75-79.
Grandin, T (1998). Handling of crippled and nonambulatory livestock. Animal Welfare Information Center Bulletin 9(1-2): 1-2, 12-13.
Jago, J.G., C.C. Krohn, and L.R. Matthews (1999). The influence of feeding and handling on the development of the human-animal interactions in young catle. Applied Animal Behaviour Science 62: 137-151.
Kronfeld, D.S. (2000). Recombinant bovine somatotropin and animal welfare. Journal of the American Veterinary Medical Association 216: 1719-1722.
Lensink, B.J., I. Veissier, and L. Florand. (2001). The farmers' influence on calves' behaviour, health and production of a veal unit. Animal Science. 72: 105-116.
Morgensen, L., C.C. Krohn, and J. Foldager (1999). Long-term effect of housing method during the first three months of life on human-animal relationship in female dairy cattle. Acta Agriculturae Scandinavica. Section A, Animal Science 49: 163-171.
Munksgaard, L., A.M. de Passille, J. Rushen, K. Thodberg, and M.B. Jensen (1977). Discrimination of people by dairy cows based on handling. Journal of Dairy Science 65: 1106-1112.
Rushen, J., A.M. de Passille, and L. Munksgaard (1999). Fear of people by cows and effects on milk yield, behavior, and heart rate at milking. Journal of Dairy Science 82: 720-727.
Rajkondawar, P.G., N. Neerchal, M.A. Varner, B. Erez, A.M. Lefcourt, R.M. Dyer, and U. Tasch. (2001). Development of a bovine lameness index that correlates visual lameness scores to measurable limb movement variables--a pilot study. Journal Animal Science 79: 16 (Suppl. 1).
Ravagnolo, O, I. Misztal, and G. Hoogenboom. (2000). Genetic component of heat stress in dairy cattle, development of heat index function. Journal Dairy Science. 83: 2120-2125.